Abstract: Lung cancer remains the leading cause of cancer mortality worldwide chiefly due to our inability to detect the disease at its earliest stage and the lack of interventions to prevent its development in those at highest risk. The rate-limiting step to developing new approaches for lung cancer detection and prevention is our lack of understanding of the earliest molecular and cellular changes associated with lung carcinogenesis. We propose to develop a high-resolution, multidimensional genetic, molecular, and cellular atlas of pre-cancerous lung lesions and their surrounding microenvironment for lung squamous cell carcinoma and adenocarcinoma, the two most common subtypes of lung cancer. We will leverage unique retrospective and prospective cohorts assembled at multiple medical centers via our Biospecimen Unit to collect, annotate, and process premalignant lesion biospecimens of the lung and airway. Our Characterization Unit will apply existing and emerging molecular profiling tools to characterize the genomic, transcriptomic, and proteomic landscape of these lesions. Pipelines for standardized multidimensional data processing, quality control, analysis and integration will be developed by our Data Analysis Unit, leading to creation of a web-based portal for data dissemination and online integrative analysis to benefit the greater research community. Cross-sectional sampling of premalignant squamous and adenomatous lesions adjacent to early stage cancer will enable development of a spatial map that will provide insights into the evolution of premalignant cells and their microenvironment. Our longitudinal study of airway premalignant squamous lesions that progress toward or regress away from invasive carcinoma will provide both a temporal and spatial map of the molecular determinants of invasive carcinoma. We will also leverage this longitudinal study to demonstrate the clinical utility of our Lung Pre- Cancer Atlas through development of prognostic biomarkers of premalignant progression that can be applied clinically for precision management, as well as to stratify patients with aggressive premalignant squamous lesions into early-phase intervention trials. Successful completion of the Atlas will be accelerated by: (1) a highly-coordinated Administrative Core that will facilitate interactions within and across Units, as well as the exchange of data, methods, and tools with other centers within the HTAN; and (2) partnerships with ongoing NCI, foundation, and industry lung premalignancy initiatives. Our Lung Pre-Cancer Atlas will ultimately serve as a resource for the medical and scientific communities to enable the development of biomarkers for early detection and risk stratification, as well as identification of novel targets for therapies that will intercept the development of lung cancer.